When a liquid packed material such as a liquid material like soups, flavorings, oils, liquors, dressings, etc., a viscous stuff like a mustard, a green horseradish paste, etc. or others is poured from a package body of a flexible package bag filled with the liquid packing material, as disclosed in Patent Document 1, the pouring is generally and traditionally performed by tearing a joint portion of the package bag defining a filling space for the packed material such as heat seal or the like from a position of a tear-inducing flaw such as I-shaped notch, V-shaped notch or others formed on an outer edge of the joint portion to reach at least the filling space for the packed material with fingers, or by cutting a corner of the package bag with scissors or the like.